While the site was occupied by a castle from the 15th century, the current Akō Castle is an Edo-period construction dating from 1661. Established by Asano Naganao by command from the Tokugawa shogunate, the castle took 13 years to build. Like most other feudal fortresses, in 1873 the castle was dismantled and abandoned after the Meiji Restoration. Many of its towers and fortifications have been rebuilt in recent years. Somewhat curiously, the castle site hosts a donjon foundation, but an actual tenshu was never approved by the shogunate and thus never built.